The disclosed embodiments relate generally to a method for operating a print processing system and, more specifically, to a method for managing one or more print processing queues by dynamically setting job sequencing rules in accordance with conditions to which the printing system is being subjected.
Conventional print shops typically are organized in a fashion so that related equipment is grouped together. For example, printing equipment may be grouped and located together, while finishing equipment may be grouped and located in another location. Thus, the print shop may be set up to have a printing department, a finishing department, and other departments corresponding to the type of process or operation that is performed within that department. The organization of a print shop is typically often independent of print job complexity, print job mix and total print job volume.
When a new print job arrives, the print job sequentially passes through each department until the print job is completed. The conventional approach can lead to significant time delays, as well as increased work-in-progress and inventory costs.
In accordance with an improved approach, a print shop may be reorganized into autonomous cells as disclosed in U.S. Pat. No. 7,079,266 to Rai et al., the pertinent portions of which are incorporated by reference. For each autonomous cell in a corresponding group, resources (e.g., equipment or stations) are grouped together according to different job classes commonly encountered by a specific print shop.
In the type of print shop contemplated by the '266 patent, print jobs (requiring one or more print processing related operations) are communicated to the print shop for handling by one or more autonomous cells. Prior to communicating the jobs to the one or more cells, a server is used to schedule processing of the jobs (or portions thereof) at the one or more cells. Scheduling systems suitable for use in a given print shop environment are disclosed in U.S. Pat. No. 7,051,328 to Rai et al. and U.S. Pat. No. 7,065,567 to Squires et al.
U.S. Pat. No. 7,051,328 discloses a print workflow including a workflow mapping module that determines a workflow of one of several document processing jobs for processing. A job description module may be used to split at least some of document processing jobs into sub-jobs for processing by the printing devices in the cells. Additionally, a print cell controller, at any one of the cells for receiving at least one sub-job, can be used to further split a sub-job into lots for processing among devices in a given cell. The printing workflow system of the '328 patent permits distribution of document processing jobs throughout a network environment.
The '328 patent further discloses a method of assigning sub-jobs to available cells in a priority workflow system for printing a product-type. The method includes identifying the maximum capacity of the available cells to print the product type. The current capacity of each of the available cells to print product type is also identified. Based on the maximum capacity and current loading of each of the available cells, a current capacity of each of the available cells for printing the product-type is determined. At least one of the available cells is assigned for printing.
U.S. Pat. No. 7,065,567 discloses a system for scheduling a document-processing job in a printing workflow system. The scheduling system includes first and second modules for determining whether the document processing job in a printing workflow system can be processed by one or by a plurality of cells, and determining the time it would take to process the document processing job in the first module. The scheduling system includes a third module for determining timing parameters to accomplish the document-processing job based on the information in the second module. The scheduling system includes a fourth module for applying the timing parameters to one or more cells to process the document processing job by a specified due date. Finally, the scheduling device includes a fifth module for queuing the document processing job in one or more cells based on the information from the fourth module to efficiently process the document processing job by the specified due date.
The pertinent portions of all of the above-mentioned patents are incorporated herein by reference.
U.S. Pat. Nos. 7,051,328 and 7,065,567 appear to contemplate a scheduling approach in which job sequencing rules used by a cell-controller are fixed for a corresponding print shop. These are determined by an assessor who simulates a set of jobs (using a suitable assessment tool) and determines which rule(s) best meets the requirements of the print shop. Examples of known print job sequencing rules include, among others, “Least Slack Time (LST),” “Earliest Due Date (EDD),” “Shortest [Remaining] Processing Time (SPT),” First-In-First-Out (FIFO),” “Last-In-First-Out (LIFO)” or “Maximum Processing Time (MPT).” It has been found that assigning one or more job sequencing rules to a set of queues in a fixed manner can, during given time intervals, lead to degraded shop performance since the effectiveness of at least some rules, based on various factors, can change significantly. For instance, at one utilization level a FIFO rule may result in very acceptable job turnaround for a given cell, while at another utilization level, the job turnaround for the same cell may be wholly unacceptable. Accordingly, it would be desirable to provide a methodology that permits a print shop to dynamically adjust job sequencing rule usage across cells so as to optimize cell processing capability.
In one aspect of the disclosed embodiments there is disclosed a method of ordering print jobs in a print queue. The print queue is operatively associated with a cell having one or more print processing devices for processing print jobs. The method includes: (A) storing a first set of at least two print jobs in the print queue; (B) corresponding a first print job sequencing rule with the print queue, the first print job sequencing rule dictating a first print job sequence in which the first set of at least two print jobs are to be processed; (C) processing the first set of at least two print jobs with the cell in accordance with the first print job sequencing rule; (D) storing a second set of at least two print jobs in the print queue; (E) performing simulations to determine if the second set of at least two print jobs should be processed in accordance with the first print job sequencing rule or a second print job sequencing rule, the second print job sequencing rule dictating a second print job sequence in which the second set of at least print jobs are to be processed, wherein the first print job sequence is different than the second print job sequence; (F) determining, with said simulations of (E), whether the second set of at least two print jobs should be processed in accordance with the first print job sequencing or the second print job sequencing rule; and (G) when it is determined that the second set of at least two print jobs should be processed in accordance with the second print job sequencing rule, changing the correspondence of the print queue from the first print job sequencing rule to the second print job sequencing rule.
In another aspect of the disclosed embodiments there is disclosed a method of ordering print jobs in a print queue. The print queue being is operatively associated with a cell having one or more print processing devices for processing print jobs. The method includes: (A) storing one set of at least two print jobs in the print queue; (B) processing the one set of at least two print jobs with the cell and a first print job sequencing rule, wherein the first print job sequencing rule dictates a first print job sequence in which print jobs stored in the print queue are to be processed; (C) storing another set of at least two print jobs in the print queue; (D) simulating processing of the other set of at least two print jobs in the cell with the first sequencing rule to obtain a first print job processing indicator; (E) simulating processing of the other set of at least two print jobs in the cell with a second print job sequencing rule to obtain a second print job processing indicator, wherein the second print job sequencing rule dictates a second print job sequence in which print jobs stored in the print queue are to be processed, and wherein the first print job sequence is different than the second print job sequence; (F) comparing the first print job processing indicator with the second print job processing indicator; and (G) based on said comparing of (F), processing the other set of at least two print jobs with the cell in accordance with one of the first print job sequencing rule and the second print job sequencing rule.